<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>常量</title>
</head>
<body>
  <script>
    //常量不允许重新赋值，声明的时候必须赋值
    //不需要重新赋值的数据使用const
    const pi = 3.14
    console.log(pi);
     
  </script>
</body>
</html>